Thermally Induced Stresses and Deformations in Angle-Ply Composite Tubes

Abstract

The effects of a uniform temperature change, from cure, on the stresses, axial expan sion, and thermally-induced twist for four specific angle-ply tube designs are considered. The study was conducted in the context of using tubes as major structural components in space structures. The four designs are: ( + Ø/ - Ø/0₄₀/ - Ø/ + Ø); (+Ø ₂/0₄₀/-Ø ₂) ( + Ø ₂/ - Ø ₂/0₄₀); and (0₄₀/ + Ø ₂/ - Ø ₂). All tubes have off-axis fibers for holding the axial layers together and for providing some measure of torsional rigidity. All four designs have the same volume fraction of off-axis layers. In addition to considering smgle material tubes made of P75s/934, hybrid tubes using T300/934 in the off-axis layers and P75s/934 in the axial layers are studied. The stresses and deformations in the tubes are studied as a func tion of the four designs, the off-axis angle, and as a function of single-material and hybrid construction. The torsional and axial stiffnesses of the tubes are also computed. The study concludes that tube design has a minor influence on the stresses, axial stiffness, and axial thermal expansion. These are more a function of off-axis angle and material selection. On the other hand, because of the position of the + Ø and - Ø layers, both relative to each other and relative to the center of the tube, tube design does influence thermally-induced twist and torsional stiffness. None of the above designs is free of thermally-induced twist. In addition to tube design, the off-axis angle and material selection also influence thermally-induced twist and torsional stiffness.

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